Radio variable rheostat



Apr. 17,1923. 1,452,399

- H. W. TOMPKINS RADI O VARIABLE RHEOS TAT Filed Au'P-j. 2.- 1922 Patented A r. .17, 1923.

-' UNITED STATES PATENT OFFICE.

HERMAN TOMPKINS, OF GREENSBURG. PENNSYLVANIA.

RADIO VARIABLE RHEOSTAT.

Application nla August 2 1922. Serial No. 579,203.

- tion, such as will enable. others skilled in the art to Which-it appertains-to make and use thes'ame.

The present invention has relation to radio apparatus and more particularly to a.

ther objects and advantages will be apparent and suggest themselvesas the nature of the inventionis understood;

While the drawings illustrate an embodiment of the invention it is to be understood that'in adapting the-same topme'et' different conditions and requirements,yarious changes in the'form, proportion and minor details of construction may be resorted to without de-c parting from the nature of the invention. Referring to the accompanying drawings forming .a part of the application, p

Figure 1 is a front view'of a radio variable rheostat embodying the invention,

Figure 2 is a side-view thereof, Figure 3 is a horizontal sectionon the line 33 of Figure 2, s Figure 4 is a detail perspective view of the hub, and

Figure 5 is a v ew similar to Figure 2 showing a difierent arrangement.

Corresponding and like parts are referred to in the following description and designated in" the several views ofthe drawings by like reference characters.

The numeral 1 designates a panel of a radio apparatus to whichthe' rheostat is attached. 2 designates a metal base plate attached to the panel 1 by means of screwsfi or analogous fastening means. A hub 4 is mounted on the base plate 2 and pivoted thereto'by means of apin'5. The sides of the hub 4 are fiat and parallel and the edge is broad and calibrated as indicated at 6 to indicate the resistance in mmit. .A handle 7 pro- .8 arerof metal so asto form jects outwardly from the edge of the'hub 4 and provides convenient means for rotating the same. A blade'8 is attached to the hub 4 at a point diametrically opposite the handle 7 and projects from the hub in an opposite direction to the handle 7 The parts 7 and 8 may be secured to' the hub 4 in any preferred way. The hub 4 and blade a part of the Cl'I'Cllll].

A semicircular. support 9' of insulating material such as fibre, hard rubber or the like, is attached at its ends to the base plate 2 and is arranged concentric with the pivot 5 of the hub 4. Abinding post 10 connects one end of the support 9 to the base plate 2 and a binding post 11 connects the opposite end of the -support 9 tothe other end of the base plate 2. The binding post 10 is in electric connection with the base plate 2, whereas the binding post 11 is electrically insulated from the base plate 2. The lead wires (not shown) are adapted to be connected to the binding posts 10'and 11. A resistance wire '12 is wound-about the support 9 andits ends are connected to the respective bindmg posts 10 and 111 The outer end of the blade 8 is in electrical contact with the resistance wire 12 and its position determines the resistance in the circuit.

The lead wire, connected to the binding post 10 is in electric connection with the re sistance wire 12 and blade 8 and the lead wire connected to the binding post 11 is in electric connection with the resistance wire 12 only. Owing to the fact that an electric current tends to travel in the path of least resistance, it will be understood that the circuit is from binding post 10 through plate 2, hub 4, blade 8 and resistance wire 12 tobinding post 11. The position of the blade 8 determines the length of resistance in the circuit and the same is indicated by the .graduations 6 on the hub 4. When the parts are inplace, the base plate 2, a portion of the hub 4, and the handle? appear on the front side of the panel, whereas the remain- 'ing parts are disposed upon the rear side of the anel and are hidden'from view.

As sliown in Figure 5, the base plate 2 may bearranged upon the inner or rear side of the panel, thereby obviating detachment therefrom of the support 9 and the resistance 12 when placing the parts in position lated therefrom, and a metalblade-carried or renio'vingthem from-the panel. Obviously any number of cooperating parts. may

be applied in gang to the one base plate. What is claimed is; w a 1. A radiosvariable rheostat comprising a metal base plate, a metal hub pivotally;

by the hub and in electric connection with s the resistance to bring. more or less'thereof into circuit.

2. A variable ratus comprising a base "plate having a slot therein andadapted to be secured to a panel of aradio apparatus, a disk shaped hub member positioned in said slot and pivoted 'to said plate, a handle for-rotating said hub member and positioned on the outer side of said panel, an arcuate support ofinsulating rheostat for radio... appamaterialsecured at its ends to said plate and concentric with said high, said support positioned at the inner side of said panel, a

resistance Wire mounted upon said support and having one end electrically connected Withthe hub, the opposite end of said, resistance Wire being insulated from the hub and adapted to have a lead ivire connected thereto, a blade on said hub opposite the point at which the handle is secured and in" contact with the resistance wirefsaid hub adapted to be rotated and carry said blade and'move the same along the resistance wire to bring more o-rless of the wire into the circuit, and said hub having its edge calibrated to indicate the resistance offered by the wirewhen the hub is in predetermined positions v Intestimony whereof Ijaiiix my signature in presence of two witnesses,

rIER AN W. TOMPKINS. Witnesses: I i

EDWARD J. GIL ORE,

N. A. Mrnns. 

